The Atlantic staff writer Adam Serwer explains how racism and white nationalism were deeply embedded in America not just from its founding, but throughout the 20th century — and how one man corralled those ideas into a grand pseudo-scientific theory that influenced U.S. immigration policy and eventually Nazi Germany. His article about that man, Madison Grant, is called "White Nationalism's Deep American Roots." Email the show at samsanders@npr.org Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy